Method, system and apparatuses for transferring session request

ABSTRACT

A method for transferring a session request including: acquiring a routing table related to a session during establishing the session; the routing table recording the address information of an AAA proxy server related to the session; transferring a session request of the session according to the address information of the AAA servers recorded in the routing table upon receiving the session request of the session. A system and a plurality of apparatuses for transferring a session request are provided as well. By the solution, all session requests of the session may be ensured to be transferred via the same route.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Reissue Application of patent application Ser. No.11/680,634 filed on 1 Mar. 2007, issued as U.S. Pat. No. 7,707,293 B2 on27 Apr. 2010 is a continuation of International Application No.PCT/CN2006/001305 filed on Jun. 13, 2006. This application claims thebenefit of Chinese Patent Application No. 200510105753.X filed on Sep.27, 2005. The disclosures of the above applications are incorporatedherein by reference.

FIELD

The present disclosure relates to the field of mobile communicationtechnology, and particularly to a method, a system and apparatuses fortransferring a session request.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

At present, the 3G network (The Third Generation Network) is graduallyevolving into a full IP network. Not only network entities supporting IPare used in the core network and IP based techniques are used in theaccess network, terminals also become IP clients that may be activated.In the 3G network, a terminal may move in home network, or roam to anetwork of other operators. No matter whether the terminal roams, whenthe terminal accesses a network and uses the services provided by theoperator, the network side will execute a strict AAA (Authentication,Authorization and Accounting) procedure to the terminal, i.e.authenticating the terminal accessed first, and verifying the validityof the terminal identity; authorizing the terminal appropriate rightaccording to the type of the service applied by the terminal after theauthentication is completed; and finally charging according to theresources occupied by the terminal.

FIG. 1 is a conventional flowchart illustrating the process oftransferring a session establishment request. Referring to FIG. 1,suppose that there is one intermediate network between a visited networkof a terminal and a home network of the terminal, in the related art,when the terminal roams and needs to establish a session connection, theprocess of transferring the session establishment request by networknodes is implemented by randomly selecting AAA proxy servers of thenetworks, which comprises the following steps:

Step 101: an AAA client in a WLAN (Wireless local network) accessnetwork of the visited network of a terminal receives a sessionestablishment request sent from the terminal.

Step 102: the AAA client randomly selects a first AAA proxy server fromthe AAA servers of the visited network, and sends the sessionestablishment request to the first AAA proxy server.

Step 103: the first AAA proxy server selects a second AAA proxy serverfrom the AAA servers of the intermediate network, and sends the sessionestablishment request to the second AAA proxy server.

Step 104: the second AAA proxy server selects a destination AAA serverfrom the AAA servers of the home network of the terminal, and sends thesession establishment request to the destination AAA server.

After a session connection is established via the above process as shownin FIG. 1, if the terminal initiates other related requests of thissession, such as a session termination request, in the WLAN accessnetwork of the visited network during the session or at the end of thesession, network nodes will send the session termination request to thedestination AAA server of the home network of the terminal by randomlyselecting AAA proxy servers as well. That is, the AAA client of thevisited network selects a third AAA proxy server from the AAA servers ofthe visited network, and sends the session establishment request to thethird AAA proxy server; the third AAA proxy server selects a fourth AAAproxy server from the AAA servers of the intermediate network, and sendsthe session establishment request to the fourth AAA proxy server; thefourth proxy server sends the session termination request to thedestination AAA server.

It can be seen from the above descriptions, in the related art, if aterminal roams, the network side needs to randomly select AAA proxyservers of the network for transferring each session request of the samesession of the terminal. For example, for each session request, the AAAclient needs to randomly select an AAA proxy server of the visitednetwork of the terminal; the selected AAA proxy server also needs torandomly select an AAA proxy server of the intermediate network. In thisway, it can not be ensured that all the session requests related to onesession are transferred via the same AAA proxy servers. For example, inthe aforesaid process, the session establishment request is transferredby the first AAA proxy server of the visited network and the secondproxy server of the intermediate network; the subsequent sessiontermination request, however, is transferred by the third AAA proxyserver of the visited network and the fourth AAA proxy server of theintermediate network. The first and third AAA proxy servers as well asthe second and fourth AAA proxy servers are usually not the same. Thus,in the related art, different AAA proxy servers are used to transferdifferent session requests of the same session.

The inventor of the present invention found in the inventing processthat, since an AAA proxy server needs to constantly modify the sessionstate maintained by the AAA proxy server according to the receivedsession request, if different AAA proxy servers are used fortransferring different session requests of the same session, each AAAproxy server will be unable to maintain a correct session state, whichmay cause a series of problems such as errors in charging and errors inIP access control. For example, in the visited network, the first AAAproxy server is selected for transferring the session establishmentrequest, and the first AAA proxy server will create the sessioncorrespondingly. However, for the session termination request transfer,the third AAA proxy server of the network is used. Since the sessiontermination request is not transferred by the first proxy server, thefirst AAA proxy server may not obtain the information on the sessiontermination, and thus will not convert the state of the session intotermination and will not end the processing of the created session,which may cause a series of problems such as errors in charging anderrors in IP access control.

SUMMARY

Embodiments of the present invention provide a method for transferring asession request, which may ensure all requests of a session to betransferred via same AAA servers.

The technical solution in accordance with the present invention is asfollows:

A method for transferring a session request includes:

acquiring routing information of a session;

transferring a session request of the session according to the routinginformation.

The routing information of the session includes:

address information of an Authentication, Authorization and Accounting(AAA) proxy server corresponding to a request of the session.

The step of acquiring the routing information includes:

acquiring the address information of the AAA proxy server correspondingto the session by transferring a session establishment request of thesession;

and the session request of the session is a session request transferredfollowing the session establishment request during the session.

The step of acquiring the routing information includes:

sending, by an AAA client of a visited network of a terminal, thesession establishment request received from the terminal to a first AAAproxy server selected from the visited network of the terminal;

writing, by the first AAA proxy server, address information of the firstAAA proxy server in the session establishment request, and sending thesession establishment request to a destination AAA server selected froma home network of the terminal;

acquiring, by the destination AAA server of the home network of theterminal, the address information of the first AAA proxy server from thesession establishment request;

sending, by the destination AAA server of the home network of theterminal, the address information of the first AAA proxy server to theAAA client of the visited network of the terminal;

the step of transferring the session request of the session according tothe routing information includes:

sending, by one party of the destination AAA server of the home networkof the terminal and the AAA client of the visited network of theterminal, the session request of the session to the first AAA proxyserver of the visited network of the terminal according to the addressinformation of the first AAA proxy server of the visited network of theterminal;

sending, by the first AAA proxy server of the visited network of theterminal, the session request of the session to the other party of thedestination AAA server of the home network of the terminal and the AAAclient of the visited network of the terminal.

The first party is the AAA client of the visited network of theterminal; the second party is the destination AAA server of the homenetwork of the terminal;

in the process of transferring the session request of the session, theaddress information which the AAA client of the visited network of theterminal takes as a foundation is the address information of the firstAAA proxy server of the visited network of the terminal is that receivedby the AAA client of the visited network of the terminal.

The step of sending the address information of the first AAA proxyserver of the visited network of the terminal to the AAA client of thevisited network of the terminal includes:

sending, by the destination AAA server of the home network of theterminal, the address information of the first AAA proxy server byappending the address information of the first AAA proxy server in oneof a session establishment response and other self-defined messages tothe AAA client of the visited network of the terminal.

The method further includes:

an intermediate network between the visited network of the terminal andthe home network of the terminal;

the step of sending the session establishment request to the destinationAAA server of the home network of the terminal including:

sending, by the first AAA proxy server, the session establishmentrequest to an AAA proxy server selected from the intermediate network;

writing, by the AAA proxy server of the intermediate network, addressinformation of the AAA proxy server of the intermediate network in thesession establishment request, and sending the session establishmentrequest to the destination AAA server of the home network of theterminal;

the process of acquiring the address information of the first AAA proxyserver from the session establishment request including:

acquiring, by the destination AAA server of the home network of theterminal, the address information of the AAA proxy server of theintermediate network from the session establishment request;

the process of sending the session request of the session to the secondparty further including:

sending, by the first party, the session request of the session to theAAA proxy server of the intermediate network according to the addressinformation of the AAA proxy server of the intermediate network.

The first party is the destination AAA server of the home network of theterminal and the second party is the AAA client of the visited networkof the terminal;

the step of sending the session request of the session according to theaddress information of the AAA proxy server of the intermediate networkincludes:

sending, by the destination AAA server of the home network of theterminal, the session request of the session containing the addressinformation of the first AAA proxy server of the visited network of theterminal to the AAA proxy server of the intermediate network accordingto the address information of the AAA proxy server of the intermediatenetwork;

sending, by the AAA proxy server of the intermediate network, thesession request of the session to the first AAA proxy server of thevisited network of the terminal according to the address information ofthe first AAA proxy server of the visited network of the terminalcontained in the session request of the session.

The method further includes:

sending, by the destination AAA server of the home network of theterminal, the address information of the first AAA proxy server of thevisited network of the terminal and the address information of the AAAproxy server of the intermediate network to the AAA client of thevisited network of the terminal;

the first party is the AAA client of the visited network of the terminaland the second party is the destination AAA server of the home networkof the terminal;

the step of sending, by the first party, the session request of thesession to the first AAA proxy server including:

sending, by the AAA client of the visited network of the terminal, tothe first AAA proxy server of the visited network of the terminal, thesession request of the session containing the address information of theAAA proxy server of the intermediate network;

the step of sending the session request of the session according to theaddress information of the AAA proxy server of the intermediate networkincluding:

sending, by the first AAA proxy server of the visited network of theterminal, the session request of the session to the AAA proxy server ofthe intermediate network according to the address information of the AAAproxy server of the intermediate network contained in the sessionrequest of the session, and sending, by the AAA proxy server of theintermediate network, the session request of the session to thedestination AAA server of the home network of the terminal.

The step of writing the address information of the AAA proxy server ofthe intermediate network in the session establishment request includes:

writing the address information of the AAA proxy server of theintermediate network in the session establishment request according to awrite-in rule.

The write-in rule is writing in successively in forward order;

the step of writing the address information of the AAA proxy server ofthe intermediate network in the session establishment request includes:

writing, by the AAA proxy server of the intermediate network, theaddress information of the AAA proxy server of the intermediate networkat the location that follows the address information of the first AAAproxy server in the session establishment request.

The method further includes:

sending, by the destination AAA server of the home network of theterminal, to the AAA proxy server of the intermediate network all theaddress information from that of the first AAA proxy server to that ofthe AAA proxy server of the intermediate network;

saving, by the AAA proxy server of the intermediate network, the addressinformation of the AAA proxy server of the intermediate network to alast record as a routing table of the AAA proxy server of theintermediate network to the destination AAA server, and saving theaddress information of the AAA proxy server of the intermediate networkto a first record as a routing table of the AAA proxy server of theintermediate network to the terminal side, and then sending to the firstAAA proxy server all the address information from that of the first AAAproxy server to that of the AAA proxy server of the intermediatenetwork;

saving, by the first AAA proxy server, the address information of thefirst AAA proxy server to the last record as a routing table of thefirst AAA proxy server to the destination AAA server, and saving theaddress information of the first AAA proxy server to the last record asa routing table of the first AAA proxy server to the terminal side;

the step of transferring the session request of the session according tothe routing information including:

if the AAA proxy server of the intermediate network or the first AAAproxy server of the visited network of the terminal initiates asubsequent request of the session to the terminal, sending thesubsequent request of the session to the terminal side according to therouting table of the AAA proxy server of the intermediate network to theterminal side or the routing table of the first AAA proxy server of thevisited network of the terminal to the terminal side respectively;

if the AAA proxy server of the intermediate network or the first AAAproxy server initiates a subsequent request of the session to thedestination AAA server of the home network of the terminal, sending thesubsequent request of the session to the destination AAA server of thehome network of the terminal according to the routing table of the AAAproxy server of the intermediate network to the destination AAA serverof the home network of the terminal or the routing table of the firstAAA proxy server of the visited network of the terminal to thedestination AAA server respectively.

The method further includes:

maintaining, by the AAA proxy server corresponding to the session,session state of the session according to the session request of thesession and making corresponding service processing according to thesession state of the session.

The method further includes:

setting a route parameter in the session establishment request;

the step of writing address information in the session establishmentrequest including:

writing address information in the segments corresponding to the routeparameter in the session establishment request;

the process of acquiring address information including:

acquiring the address information from the segments corresponding to theroute parameter in the session establishment request.

The method further includes:

upon receiving the routing information of the session, transferring allsession requests of another session according to the routinginformation, and the session and another session relates to the samevisited network and home network of the terminal.

The method further includes:

setting, at any AAA client, a routing table of an AAA client to adestination AAA server in another network, and the routing table recordsaddress information of AAA proxy servers from the AAA client to thedestination AAA server in another network;

the step of acquiring the routing information of the session includes:

acquiring, by the AAA client, the routing table set in the AAA clientupon receiving the session request of the session sent from a terminaland aimed at the destination AAA server;

the step of transferring the session request of the session according tothe routing information includes:

sending, by the AAA client, the session request of the sessioncontaining the routing table, to the AAA proxy server according to theaddress information of the AAA proxy servers recorded in the routingtable; and

determining, by the AAA proxy server, the route for sending the sessionrequest up to the destination AAA server according to the routing tablecontained in the session request of the session.

Type of the session request of the session includes one of a Diameterprotocol and a remote authentication dial-in user service Radiusprotocol.

It may be concluded from the aforesaid that embodiments of the presentinvention has the following advantages:

In accordance with some embodiments of the present invention, routingtable is formed according to the route for transferring the sessionestablishment request, and the subsequent requests related to thesession are all transferred according to the routing table so as toensure that all the requests of the same session to be transferred viasame AAA proxy servers, thereby allowing the AAA proxy servers tomaintain a correct session state according to the session request, andthus make correct service processing corresponding to the session, suchas correct charging, correct IP access control and the like.

In accordance with the routing method for the same session as proposedin embodiments of the present invention, processing routing according tothe routing table. No matter how many AAA proxy servers are in anetwork, all the requests related to one session may be ensured to betransferred by the same AAA proxy server of the network, thereby makingthe network with remarkable expandability and operability.

In accordance with some embodiments of the present invention, each AAAproxy server may initiate a session related request to the terminal ordestination AAA server according to the routing table and the practicalservice requirement, thereby improving the manageability of the serviceand giving the invention remarkable flexibility.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a simplified conventional flowchart illustrating the processof sending a session establishment request in a related art.

FIG. 2 is a schematic diagram illustrating a reference model for WLANand 3G interworking when a terminal roams.

FIG. 3 is a flowchart illustrating the process of transferring a sessionestablishment request according to an embodiment of the presentinvention.

FIG. 4 is a flowchart illustrating the process for an AAA client toacquire a routing table according to an embodiment of the presentinvention.

FIG. 5 is a flowchart illustrating the process for an AAA proxy serverinitiating a subsequent request related to the session according to anembodiment of the present invention.

FIG. 6 is a flowchart illustrating the process of transferring a sessiontermination request according to an embodiment of the present invention.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Itshould be understood that throughout the drawings, correspondingreference numerals indicate like or corresponding parts and features.

In embodiments of the present invention, acquiring routing informationof a session and transferring session requests of the session accordingto the routing information.

There are two implementations as described bellow:

Implementation 1: pre-configure, at an AAA client of any network, arouting table which records a route from the AAA client to a destinationAAA server of other networks, i.e. the routing table records addressinformation of each AAA proxy server between the AAA client and thedestination AAA server; when receiving each session request of a sessionsent from the terminal and aiming at the destination AAA server, the AAAclient acquires the routing table pre-configured in the AAA client todetermine the routing information for sending, i.e. the addressinformation of the AAA proxy server of the next hop, and the routingtable pre-configured is contained in each session request of thesession; in this way, each AAA proxy server may acquire the routinginformation according to the routing table contained in the receivedsession request, i.e. the address information of the AAA proxy server ofthe next hop up to the destination AAA server, so that all sessionrequests of the session are ensured to be transferred through the sameroute.

Implementation 2: address information of each AAA proxy server is wrotein a session establishment request by each AAA proxy server uponreceiving a session establishment request, respectively, and finally arouting table recording the routing information of the sessionestablishment request is formed. When a subsequent request of thissession is sent, an AAA client of a visited network of a terminal, anAAA server of a home network of the terminal and each other AAA proxyserver acquire a route for sending each session request of this sessionaccording to the formed routing table, so that all session requests ofthe same session is ensured to be transferred via the same route.

The present invention will be described in detail hereinafter withreference to the accompanying drawings and embodiments, so as to makethe technical solution and merits of the present invention moreapparent.

Suppose that the implementation 2 is taken and there are twointermediate networks between the visited network and the home networkof the terminal, then the method is implemented as follows.

FIG. 2 is a schematic diagram illustrating a reference model for WLANand 3G interconnecting when a terminal roams. FIG. 3 is a flowchartillustrating the process of transferring a session establishment requestaccording to an embodiment of the present invention. Referring to FIG. 2and FIG. 3, when the terminal roams and needs to establish a sessionconnection, the process of transferring a session establishment requestincludes the following steps:

Step 301: preset a write-in rule.

Herein, the write-in rule is preset so that each AAA proxy server in thesubsequent process successively writes its own address information inthe session establishment request according to the preset write-in rule.For example, the write-in rule may be writing in successively in abackward or forward order. Suppose that the write-in rule is writing insuccessively in the forward order, the subsequent process according tothe embodiment of the present invention is implemented as follows.

Step 302: the AAA client of the visited network of a terminal receivesthe session establishment request sent from the terminal.

Step 303: the AAA client selects a first AAA proxy server from the AAAservers of the visited network, and sends the session establishmentrequest to the first AAA proxy server.

Step 304: upon receiving the session establishment request, the firstAAA proxy server writes address information of the first AAA proxyserver in the session establishment request according to the write-inrule.

Herein, the address information may be the information for uniquelyidentifying the first AAA proxy server such as the host name or portnumber of the first AAA proxy server.

In addition, since the write-in rule is writing in successively in theforward order as supposed, the first AAA proxy server writes the addressinformation of the first AAA proxy server at the first location in thesession establishment request.

Step 305: the first AAA proxy server selects a second MA proxy serverfrom the AAA servers of the intermediate network 1 connected with thefirst AAA proxy server, and sends the session establishment request tothe second AAA proxy server.

Step 306: upon receiving the session establishment request, the secondAAA proxy server writes address information of the second AAA proxyserver in the session establishment request according to the write-inrule.

Herein, since the write-in rule is writing in successively in theforward order as supposed, the second AAA proxy server writes theaddress information of the second AAA proxy server at the location thatfollows the address information of the first AAA proxy server in thesession establishment request.

Step 307: the second AAA proxy server selects a third AAA proxy serverfrom the AAA servers of the intermediate network 2 connected with thesecond AAA proxy server, and sends the session establishment request tothe third AAA proxy server.

Step 308: upon receiving the session establishment request, the thirdAAA proxy server writes address information of the third AAA proxyserver in the session establishment request according to the write-inrule.

Herein, since the write-in rule is writing in successively in theforward order as supposed, the third AAA proxy server writes the addressinformation of the third AAA proxy server at the location that followsthe address information of the second AAA proxy server in the sessionestablishment request.

Step 309: the third AAA proxy server selects a destination AAA serverfrom the AAA servers of the home network of the terminal, and sends thesession establishment request to the destination AAA server.

Step 310: upon receiving the session establishment request, thedestination AAA server acquires the address information of all the AAAproxy servers from the session establishment request and forms therouting table.

The routing table formed by the destination AAA server may be as shownin Table 1.

TABLE 1 The first AAA proxy server The second AAA proxy server The thirdAAA proxy server

It should be noted that in the process of transferring a sessionestablishment request as shown in FIG. 3, the first, second and thirdAAA proxy server will correspondingly maintain the state of this sessioncorrespondingly when they receive the session establishment request,i.e. create this session.

After the destination AAA server of the home network of the terminalacquires the routing table, i.e. the address information of the AAAproxy servers corresponding to the session establishment request, inorder to ensure that all the subsequent requests are transferred throughthe same AAA proxy servers corresponding to the session establishmentrequest, to ensure that each AAA proxy server may maintain a correctsession state, the AAA client of the visited network of the terminalmust acquire the formed routing table as well. Therefore, according tothe embodiment of the present invention, the destination AAA server ofthe home network of the terminal sends the routing table to the AAAclient of the visited network of the terminal by transferring existingsession establishment response containing the routing table or bytransferring existing or self-defined messages containing the routingtable. Referring to FIGS. 2 and FIG. 4, suppose the routing table iscontained in the existing session establishment response, the processfor the AAA client to acquire the routing table includes the followingsteps.

Step 401: the destination AAA server of the home network of the terminalsends the session establishment response containing the routing table tothe third AAA proxy server of the intermediate network 2 connected withthe destination AAA server.

Herein, since one session request and the response thereof may beensured to be transferred via the same route so far, the destination AAAserver of the home network of the terminal and the AAA proxy servers inthe subsequent process may all accurately send the session establishmentresponse containing the routing table to the next hop of the network.

Step 402: the third AAA proxy server determines whether the third AAAproxy server needs to initiate a subsequent request, if the third AAAproxy server needs to initiate a subsequent request, perform step 403;otherwise, go to perform step 404.

Herein, the third AAA proxy server determines whether the third AAAproxy server needs to initiate a subsequent session request bydetermining whether the third AAA proxy server needs to control thesubsequent session, e.g. whether the third AAA proxy server needs toterminate the session, modify the session or the like.

Step 403: the third AAA proxy server acquires the routing table from thereceived session establishment response and saves the routing table.

Herein, since the third AAA proxy server in the subsequent process mayinitiate a subsequent session request of this session to the terminalside or to the destination AAA server by using the routing table, thethird AAA proxy server may split the routing table into a routing tableof the third AAA proxy server to the destination AAA server and arouting table of the third AAA proxy server to the terminal side, andsave them according to the preset write-in rule. Since the write-in ruleis writing successively in the forward order as supposed, the routingtable of the third AAA proxy server to the destination AAA server savedby the third AAA proxy server includes the record of the third AAA proxyserver to the last record, i.e. the record of the third AAA proxyserver; and the routing table of the third AAA proxy server to theterminal side saved by the third AAA proxy server includes the record ofthe third AAA proxy server to the first record, i.e. the records of thethird AAA proxy server, the second AAA proxy server and the first AAAproxy server.

Step 404: the third AAA proxy server sends the session establishmentresponse containing the routing table to the second AAA proxy server ofthe intermediate network 1 connected with the third AAA proxy server.

Step 405: the second AAA proxy server determines whether the second AAAproxy server needs to initiate a subsequent request, if the second AAAproxy server needs to initiate a subsequent request, perform step 406;otherwise go to perform step 407.

Step 406: the second AAA proxy server acquires the routing table fromthe received session establishment response and saves the routing table.

Herein, the second AAA proxy server may also split the routing tableinto two parts accordingly, i.e. save the contents of the routing tablefrom the record of the second AAA proxy server to the last record as arouting table of the second AAA proxy server to the destination AAAserver, i.e. the second AAA proxy server and the third AAA proxy server,and save the contents of the routing table from the record of the secondAAA proxy server to the first record as a routing table of the secondAAA proxy server to the terminal side, i.e. the second AAA proxy serverand the first AAA proxy server.

Step 407: the second AAA proxy server sends the session establishmentresponse containing the routing table to the first AAA proxy server ofthe visited network of the terminal.

Step 408: the first AAA proxy server determines whether the first AAAproxy server needs to initiate a subsequent request, if the first AAAproxy server needs to initiate a subsequent request, perform step 409;otherwise, go to perform step 410.

Step 409: the first AAA proxy server acquires the routing table from thereceived session establishment response and saves the routing table.

Herein, the first AAA proxy server may also split the routing table intotwo parts accordingly, i.e. save the contents of the routing table fromthe record of the first AAA proxy server to the last record as a routingtable of the first AAA proxy server to the destination AAA server, i.e.the first AAA proxy server, the second AAA proxy server and the thirdAAA proxy server, and save the contents of the routing table from therecord of the first AAA proxy server to the first record as a routingtable of the first AAA proxy server to the terminal side, i.e. the firstAAA proxy server.

Step 410: the first AAA proxy server sends the session establishmentresponse containing the routing table to the AAA client of the visitednetwork of the terminal.

Step 411: the AAA client of the visited network of the terminal acquiresthe routing table from the received session establishment response.

Herein, the routing table acquired by the AAA client of the visitednetwork of the terminal is as shown in Table 1, i.e. the first AAA proxyserver, the second AAA proxy server and the third AAA proxy server.

Thus, the information of the AAA servers corresponding to the firstsession request of the session, i.e. the information of the AAA serverscorresponding to the session establishment request, is saved by the AAAclient of the visited network of the terminal and the destination AAAserver of the home network of the terminal according to the embodimentof the present invention. In addition, routing tables are enabled to besaved as well in each AAA proxy server needing to initiate a subsequentsession request according to the embodiment of the invention. Therefore,in the subsequent session process, each AAA proxy server with the savedrouting table may initiate a subsequent request related to this sessionto the terminal side or to the destination AAA server according to therouting tables they save, and the AAA client and the destination AAAserver of the home network of the terminal may initiate a subsequentrequest related to this session to the destination AAA server or theterminal side according to the saved routing table, respectively. Allthe requests related to this session from the first sessionestablishment request of this session to the last session terminationrequest are enabled to be transferred via the same AAA servers, so thateach AAA proxy server may be ensured to maintain a correct sessionstate.

FIG. 5 is a flowchart illustrating the process of initiating are-authentication request by an AAA proxy server. Referring to FIG. 2and FIG. 5, taking the third AAA proxy server as an example, when thethird AAA proxy server detects a time-out in this session and a need forre-authenticating the terminal, the third AAA proxy server initiates arequest related to this session, i.e. a re-authentication request to theterminal side. The implementation process includes the following steps.

Step 501: when detects a time-out in this session, the third AAA proxyserver deletes the record of the third AAA proxy server from the routingtable, and sends to the second AAA proxy server the re-authenticationrequest containing the routing table with the record of the third AAAproxy server deleted.

Herein, since the routing table of the third AAA proxy server to theterminal saved by the third AAA proxy server includes the record of thethird AAA proxy server, the second AAA proxy server and the first AAAproxy server; the third AAA proxy server may learn that there-authentication request should be sent to the second proxy server. Inaddition, after the record of the third AAA proxy server is deleted, therouting table contained in the re-authentication request includes therecords of the second AAA proxy server and the first AAA proxy server.

Step 502: the second AAA proxy server acquires the routing table fromthe received re-authentication request, deletes the record of the secondAAA proxy server, and sends to the first AAA proxy server there-authentication request containing the routing table with the recordof the second AAA proxy server deleted.

Herein, since the routing table acquired by the second AAA proxy serverincludes the records of the second AAA proxy server and the first AAAproxy server, the second AAA proxy server may learn that there-authentication request should be sent to the first AAA proxy server.In addition, after the record of the second AAA proxy server is deleted,the routing table contained in the re-authentication request includesthe record of the first AAA proxy server.

Step 503: the first AAA proxy server sends the re-authentication requestto the AAA client of visited network, according to the routing tableacquired from the received re-authentication request.

Herein, since the routing table acquired by the first AAA proxy serverincludes record of the first AAA proxy server only, the first AAA proxyserver may learn that the network where it is located is the network ofthe visited network of the terminal, and accordingly sends there-authentication request to the AAA client of this network, i.e. theAAA client of the visited network of the terminal. In addition, in thisstep, since the routing table acquired by the first AAA proxy serveronly includes the record of the first AAA proxy server, the first AAAproxy server may delete the routing table, i.e. the re-authenticationrequest sent from the first AAA proxy server to the AAA client no longerincludes the routing table.

Step 504: the AAA client of the visited network of the terminal sendsthe re-authentication request to the terminal.

FIG. 6 is a flowchart illustrating the process of transferring a sessiontermination request according to an embodiment of the present invention.Referring to FIG. 2 and FIG. 6, in this embodiment, the process ofsending the subsequent request related to this session, i.e. the sessiontermination request, by the terminal includes the following steps.

Step 601: when receiving the session termination request sent from theterminal, the AAA client of the visited network of the terminal sends tothe first AAA proxy server, according to the routing table saved in theAAA client, the session termination request including the routing tablesaved in the AAA client.

Herein, the routing table saved in the AAA client and included in thesession termination request is as shown in Table 1, i.e. the records ofthe first AAA proxy server, the second AAA proxy server, the third AAAproxy server; the AAA client therefore may learn, according to therouting table, that the session termination request should be sent tothe first proxy server.

Step 602: the first AAA proxy server acquires the routing table from thesession termination request, deletes the record of the first AAA proxyserver from the routing table, and sends to the second AAA proxy serverthe session termination request containing the routing table with therecord of the first AAA proxy server deleted.

Herein, the routing table acquired by the first AAA proxy serverincludes the records of the first AAA proxy server, the second AAA proxyserver, the third AAA proxy server; the first AAA proxy server deletesthe first record from the routing table because the first record is therecord of the first AAA proxy server. In this way, the routing tableincluded in the session termination request includes the records of thesecond AAA proxy server and the third AAA proxy server; and the firstAAA proxy server may learn, according to the routing table, that thesession termination request should be sent to the second AAA proxyserver.

Step 603: the second AAA proxy server acquires the routing table fromthe session termination request, deletes the record of the second AAAproxy server from the routing table, and sends to the third AAA proxyserver the session termination request including the routing table withthe record of the second AM proxy server deleted.

Herein, the routing table acquired by the second AM proxy serverincludes the records of the second MA proxy server, the third AM proxyserver. The second MA proxy server deletes the first record from therouting table because the first record is the record of the second MAproxy server. In this way, the routing table included in the sessiontermination request only includes the record of the third AAA proxyserver; and the second AAA proxy server may learn, according to therouting table, that the session termination request should be sent tothe third AAA proxy server.

Step 604: the third AAA proxy server acquires the routing table from thesession termination request, and sending the session termination requestto the destination AAA server.

Herein, the routing table acquired by the third AAA proxy server onlyincludes the record of the third AAA proxy server, so the third AAAproxy server may learn that the session termination request should besent to the destination AAA server. In addition, in this step, since therouting table acquired by the third AAA proxy server only includes therecord of the third AAA proxy server, the third AAA proxy server maydelete the routing table, i.e. the routing table is no longer containedin the session termination request sent from the third AAA proxy serverto the destination AAA server.

It should be noted that, when the subsequent request related to thissession is transferred as shown in FIG. 5 and FIG. 6, upon receiving thecorresponding session request, each AAA proxy server willcorrespondingly modify the state of this session it maintains, so that acorrect state of the session and a proper service processing may beensured. For example, in the process as shown in FIG. 6, when receivingthe session termination request, the first, the second and the third AAAproxy servers respectively convert the state of this session into“termination” to ensure the correctness of the session state. In thisway, the first, the second and the third AAA proxy servers may implementproper session related processing according to the correct sessionstate, such as release the resources occupied by this session, andgenerate correct charging information and the like.

In the above embodiments, the routing table may be modified according tothe actual requirement of service. In another word, when receiving asession request or session response of this session which contains therouting table, if an AAA proxy server hopes that the subsequent sessionrelated request will not be forwarded by itself again, the AAA proxyserver may delete its own address information from the routing tablebefore sending the session request or session response. In this way,when the subsequent session related request is transferred, in othernetworks, the routing table is still transferred by the original AAAproxy servers; in the network of which the AAA proxy server is deleted,another AAA proxy server is selected; and the address information of theAAA proxy server selected is added to the location corresponding to theAAA proxy server deleted in the routing table so that a new routingtable is formed; then the new routing table is sent to the other sidevia a response message; in the subsequent process, the new routing tableis used for transferring the subsequent request of this session.

Furthermore, based on the implementing procedure of the above embodimentof the present invention, i.e. a routing table has been saved in the AAAclient, when the AAA client receives a session establishment request ofanother session, if the home network of the terminal corresponding tothe another session is the same as the home network of the terminalcorresponding to the saved routing table, i.e. the visited networks andthe home networks for the two sessions are the same respectively, theAAA client may add the saved routing table into the sessionestablishment request of the another session. In this way, the AAAclient and all the AAA proxy servers of the network transfer the sessionestablishment request of the another session according to the routingtable contained in the session establishment request of the anothersession, in addition, the subsequent session request related to theanother session is also transferred according to such a routing table,so that all session requests related to the another session may betransferred via the same route.

In the above embodiment of the present invention, the type of eachsession request and session request response may be any of the AAAprotocol messages, such as the Diameter or Radius protocol message. Whena routing table is formed by writing in address information, the processmay be implemented by adding a parameter to the session establishmentrequest of the AAA protocol. For example, a parameter Route-List may beadded to the Radius protocol's message and each AAA proxy server writesits own address information successively in the segment corresponding tothe parameter Route-List; therefore, the subsequent process of acquiringthe routing table may be implemented via the parameter Route-List.

In the above embodiment of the present invention, the implementingprocedure is described by supposing that there are two intermediatenetworks between the visited network and the home network of theterminal. In practice, there may be more or less intermediate networksor no intermediate network between the visited network and the homenetwork of the terminal, but the principle for implementation is thesame as that of the above embodiment.

The foregoing is only preferred embodiments of the present invention andis not for use in limiting the protection scope thereof. Anymodification, equivalent substitution, improvement within the spirit andprinciple of the invention should be covered in the protection scope ofthe invention.

1. A method for transferring a session request, comprising: acquiring,by an Authentication, Authorization and Accounting, (AAA,)client in avisited network of a terminal, a routing table related to a session;wherein the routing table is generated during transferring a sessionestablishment request of the session and records the address informationof at least one Authentication, Authorization and Accounting (AAA) proxyserver between the AAA client in the visited network of the terminal anda destination AAA server in a home network of the terminal;transferring, by the AAA client of the visited network of the terminal,the a session request of the session carrying the routing table to afirst AAA proxy server of the visited network of the terminal accordingto the address information of the first AAA proxy server recorded in therouting table upon receiving the session request of the session sendingfrom the terminal; acquiring, by the first AAA proxy server of thevisited network of the terminal, a route for sending the session requestof the session, according to the routing table carried in the receivedsession request; transferring, by the first AAA proxy server of thevisited network of the terminal, the session request of the sessioncarrying the routing table with a record of the first AAA serverdeleted, to the an AAA proxy server of the an intermediate network orthe destination AAA server of the home network of the terminal,according to the route for sending the session request of the session;and transferring all session requests of another session each subsequentrequest of the session between the AAA client and the destination AAAserver through the AAA proxy server according to the routing tablerelated to the session, wherein the another session and the sessionrelate to the same visited network of the terminal and the same homenetwork of the terminal so that all requests of the session to betransferred via same AAA proxy servers.
 2. The method of claim 1,wherein the step of generating the routing table related to the sessionduring transferring a session establishment request of the sessioncomprises: sending, by the AAA client of the visited network of theterminal, a session establishment request of the session to a first AAAproxy server selected from the visited network of the terminal uponreceiving the session establishment request of the session from theterminal; writing, by the first AAA proxy server of the visited networkof the terminal, the address information of the first AAA proxy serverin the session establishment request of the session, and sending thesession establishment request of the session to the destination AAAserver selected of the home network of the terminal; saving, by thedestination AAA server of the home network of the terminal, the addressinformation of the first AAA proxy server as the routing table relatedto the session; sending, by the destination AAA server of the homenetwork of the terminal, the routing table related to the session to theAAA client of the visited network of the terminal; saving, by the AAAclient of the visited network of the terminal, the routing table relatedto the session.
 3. The method of claim 2, wherein the step of sending bythe destination AAA server of the home network of the terminal therouting table related to the session to the AAA client of the visitednetwork of the terminal comprises: sending, by the destination AAAserver of the home network of the terminal, the routing table to thefirst AAA proxy server of the visited network of the terminal accordingto the address information of the first AAA proxy server recorded in therouting table; sending, by the first AAA proxy server of the visitednetwork of the terminal, the routing table related to the session to theAAA client of the visited network of the terminal.
 4. The method ofclaim 2, wherein the step of sending by the destination AAA server ofthe home network of the terminal the routing table related to thesession to the AAA client of the visited network of the terminalcomprises: sending, by the destination AAA server of the home network ofthe terminal, a session establishment response of the session or otherself-defined messages carrying the routing table related to the sessionto the AAA client of the visited network of the terminal.
 5. The methodof claim 2, further comprising: sending, by the destination AAA serverof the home network of the terminal, the session request of the sessionto the first AAA proxy server of the visited network of the terminalaccording to the address information of the first AAA proxy serverrecorded in the routing table related to the session; sending, by thefirst AAA proxy server of the visited network of the terminal, thesession request of the session to the AAA client of the visited networkof the terminal.
 6. The method of claim 1, wherein there is anintermediate network between the visited network of the terminal and thehome network of the terminal, the step of acquiring the routing tablerelated to the session comprises: sending, by the AAA client of thevisited network of the terminal, the session establishment request ofthe session to a first AAA proxy server selected from the visitednetwork of the terminal upon receiving the session establishment requestof the session from the terminal; writing, by the first AAA proxy serverof the visited network of the terminal, the address information of thefirst AAA proxy server in the session establishment request of thesession, and sending the session establishment request of the session toan AAA proxy server selected from the intermediate network; writing, bythe AAA proxy server of the intermediate network, the addressinformation of the AAA proxy server of the intermediate network in thesession establishment request, and sending the session establishmentrequest to a destination AAA server selected from the home network ofthe terminal; saving, by the destination AAA server of the home networkof the terminal, the address information of the first AAA proxy serverand the address information of the AAA proxy server of the intermediatenetwork as the routing table related to the session; sending, by thedestination AAA server of the home network of the terminal, the routingtable related to the session to the AAA client of the visited network ofthe terminal; saving, by the AAA client of the visited network of theterminal, the routing table related to the session.
 7. The method ofclaim 6, wherein the intermediate network comprises one or moreintermediate networks, and the step of writing by the AAA proxy serverof the intermediate network the address information of the AAA proxyserver of the intermediate network in the session establishment requestand sending the session establishment request to the destination AAAserver of the home network of the terminal comprises: writing, by an AAAproxy server of each intermediate network, the address information ofitself in the session establishment request of the session uponreceiving the session establishment request of the session, and sendingthe establishment request of the session to one of an AAA proxy serverof a next intermediate network and the destination AAA server of thehome network of the terminal.
 8. The method of claim 6, wherein the stepof sending by the destination AAA server of the home network of theterminal the routing table related to the session to the AAA client ofthe visited network of the terminal comprises: sending, by thedestination AAA server of the home network of the terminal, the routingtable related to the session to the AAA proxy server of the intermediatenetwork according to the address information of the AAA proxy server ofthe intermediate network recorded in the routing table related to thesession; sending, by the AAA proxy server of the intermediate network,the routing table related to the session to the first AAA proxy serverof the visited network of the terminal according to the addressinformation of the first AAA proxy server recorded in the routing tablerelated to the session; sending, by the first AAA proxy server of thevisited network of the terminal, the routing table related to thesession to the AAA client of the visited network of the terminal.
 9. Themethod of claim 8, wherein the step of writing the address informationin the session establishment request comprises: writing the addressinformation in the session establishment request successively in forwardorder; the step of writing the address information of the AAA proxyserver of the intermediate network in the session establishment requestcomprises: writing, by the AAA proxy server of the intermediate network,the address information of the AAA proxy server of the intermediatenetwork at the location that follows the address information of thefirst AAA proxy server in the session establishment request.
 10. Themethod of claim 9, further comprising: upon receiving the routing tablerelated to the session, saving, by the AAA proxy server of theintermediate network, the record of the address information of the AAAproxy server of the intermediate network to a last record of the routingtable as a first routing table from the AAA proxy server of theintermediate network to the destination AAA server of the home networkof the terminal, and saving the record of the address information of theAAA proxy server of the intermediate network to a first record of therouting table as a second routing table from the AAA proxy server of theintermediate network to the AAA client of the visited network of theterminal.
 11. The method of claim 10, further comprising: if the AAAproxy server of the intermediate network initiates a re-authenticationrequest of the session to the destination AAA server of the home networkof the terminal, sending the re-authentication request of the session tothe destination AAA server of the home network of the terminal accordingto the first routing table; if the AAA proxy server of the intermediatenetwork initiates a re-authentication request of the session to the AAAclient of the visited network of the terminal, sending there-authentication request of the session to the AAA client of thevisited network of the terminal according to the second routing table.12. The method of claim 9, further comprising: upon receiving therouting table related to the session, saving, by the first AAA proxyserver of the visited network of the terminal, the record of the addressinformation of the first AAA proxy server to a last record of therouting table as a third routing table from the first AAA proxy serverof the visited network of the terminal to the destination AAA server ofthe home network of the terminal, and saving the record of the addressinformation of the first AAA proxy server to a last record of therouting table as a fourth routing table from the first AAA proxy serverof the visited network of the terminal to the AAA client of the visitednetwork of the terminal.
 13. The method of claim 12, further comprising:if the first AAA proxy server of the visited network of the terminalinitiates a re-authentication request of the session to the destinationAAA server, sending the re-authentication request of the session to thedestination AAA server of the home network of the terminal according tothe third routing table; if the first AAA proxy server of the visitednetwork of the terminal initiates a re-authentication request of thesession to the AAA client of the visited network of the terminal,sending the re-authentication request of the session to the AAA clientof the visited network of the terminal according to the fourth routingtable.
 14. The method of claim 6, further comprising: sending, by thedestination AAA server of the home network of the terminal, the sessionrequest of the session carrying the routing table related to the sessionto the AAA proxy server of the intermediate network according to theaddress information of the AAA proxy server of the intermediate networkrecorded in the routing table related to the session; sending, by theAAA proxy server of the intermediate network, the session request of thesession carrying the routing table related to the session to the firstAAA proxy server of the visited network of the terminal according to theaddress information of the first AAA proxy server recorded in therouting table related to the session; sending, by the first AAA proxyserver of the visited network, the session request of the sessioncarrying the routing table related to the session to the AAA client ofthe visited network of the terminal.
 15. The method of claim 6, the stepof transferring, by the first AAA proxy server of the visited network ofthe terminal, the session request of the session carrying the routingtable to the AAA proxy server of the intermediate network or thedestination AAA server of the home network of the terminal, according tothe route for sending the session request of the session comprises:sending, by the first AAA proxy server of the visited network of theterminal, the session request of the session carrying the routing tablerelated to the session to the AAA proxy server of the intermediatenetwork according to the address information of the AAA proxy server ofthe intermediate network recorded in the routing table related to thesession; sending, by the AAA proxy server of the intermediate network,the session request of the session carrying the routing table related tothe session to the destination AAA server of the home network.
 16. Themethod of claim 1, further comprising: deleting, by the AAA proxyserver, the address information of the AAA proxy server from the routingtable related to the session upon receiving the session request of thesession carrying the routing table related to the session.
 17. Themethod of claim 1, further comprising: maintaining, by the AAA proxyserver related to the session, session state of the session according tothe received session request of the session and making correspondingservice processing according to the session state of the session. 18.The method of claim 2, further comprising: setting a route parameter inthe session establishment request of the session; the step of writingaddress information in the session establishment request of the sessioncomprising: writing address information in the segments corresponding tothe route parameter of the session establishment request of the session.19. The method of claim 1, wherein type of the session request of thesession comprises one of a Diameter protocol and a remote authenticationdial-in user service Radius protocol.
 20. A system for transferring asession request, comprising: an Authentication, Authorization andAccounting (AAA) client of a visited network of a terminal, adapted toselect an AAA proxy server and send a session establishment request of asession to the AAA proxy server upon receiving the session establishmentrequest of the session from the terminal; the AAA proxy server, adaptedto acquire a routing table related to the session, send the sessionestablishment request of the session carrying the routing table relatedthe session to a destination AAA server of a home network of theterminal; wherein the routing table records the address information ofthe AAA proxy server itself, the destination AAA server of the homenetwork of the terminal, adapted to save the routing table related tothe session and recording the address information of the AAA proxyserver between the AAA client in the visited network of the terminal andthe destination AAA server in the home network of the terminal, and sendthe routing table related to the session to the AAA client of thevisited network of the terminal; the AAA client of the visited networkof the terminal, the AAA proxy server and the destination AAA server ofthe home network of the terminal further adapted to transfer othersession request of the session carrying the routing table to the nexthop according the address information of the AAA proxy server recordedin the routing table related to the session upon receiving the othersession request of the session; and the AAA client of the visitednetwork of the terminal, the AAA proxy server and the destination AAAserver of the home network of the terminal further adapted to transferall session requests of another session according to the routing tablerelated to the session, wherein the another session and the sessionrelate to the same visited network of the terminal and the same homenetwork of the terminal.
 21. The system of claim 20, wherein the AAAproxy server comprises: a first AAA proxy server of the visited networkof the terminal, adapted to write the address information of the firstAAA proxy server of the visited network of the terminal in the sessionestablishment request of the session, upon receiving the sessionestablishment request of the session sent from the AAA client of thevisited network of the terminal, and send the session establishmentrequest of the session to the destination AAA server of the home networkof the terminal; the destination AAA server of the home network of theterminal comprises a first destination AAA server, adapted to save theaddress information of the first AAA proxy server of the visited networkof the terminal as the routing table related to the session, and sendthe routing table related to the session to the AAA client of thevisited network of the terminal.
 22. The system of claim 20, wherein theAAA proxy server comprises: a first AAA proxy server of the visitednetwork of the terminal, adapted to write the address information of thefirst AAA proxy server of the visited network of the terminal in thesession establishment request of the session, upon receiving the sessionestablishment request of the session sent from the AAA client of thevisited network of the terminal, and send the session establishmentrequest of the session to a selected AAA proxy server of an intermediatenetwork; the AAA proxy server of the intermediate network, adapted towrite the address information of the AAA proxy server of theintermediate network in the session establishment request and send thesession establishment request to the destination AAA server of the homenetwork of the terminal; the destination AAA server of the home networkof the terminal comprises a second destination AAA server, adapted tosave the address information of the first AAA proxy server of thevisited network of the terminal, the address information of the AAAproxy server of the intermediate network as the routing table related tothe session; and sending the routing table related to the session to theAAA client of the visited network of the terminal.
 23. AnAuthentication, Authorization and Accounting (AAA) proxy server of afirst network, comprising: a first component adapted to: write theaddress information of the AAA proxy server upon receiving a sessionestablishment request of a session; and select one of an AAA proxyserver of a second network, and a destination AAA server of a homenetwork of a terminal, and send the session establishment request of thesession with the address information of the AAA proxy server written tothe one of the AAA proxy server of the second network and thedestination AAA server; and select one of the AAA proxy server of thesecond network, an AAA client of a visited network of the terminal andthe destination AAA server of the home network of the terminal accordingto the address information of the AAA proxy server recorded in a routingtable related to the session upon receiving other session request of thesession carrying the routing table related to the session, and send theother session request of the session to the one of the AAA proxy serverof the second network, the AAA client and the destination AAA; andtransfer all session requests of another session between the AAA clientand the destination AAA server through the AAA proxy server according tothe routing table related to the session, wherein the another sessionand the session relate to the same visited network of the terminal andthe same home network of the terminal.
 24. The AAA proxy server of claim23, further comprising: a second component adapted to: save the routingtable related to the session as a first routing table from the AAA proxyserver to the AAA client, and a second routing table from the AAA proxyserver to the destination AAA server, upon receiving a session requestof the session carrying the routing table related to the session; andinitiate a session request of the session to the AAA client or to thedestination AAA server respectively according to the first routing tableor the second routing table.
 25. The AAA proxy server of claim 23,further comprising: a third component adapted to: delete the addressinformation of the AAA proxy server from the routing table uponreceiving the session request of the session carrying the routing table,and send the session request of the session carrying the routing tablewith the address information of the AAA proxy server deleted to one ofthe AAA proxy server of the second network, the AAA client and thedestination AAA server according to the routing table.
 26. A system fortransferring a session request, comprising: an Authentication,Authorization and Accounting (AAA) client of a visited network of aterminal, configured to acquire a routing table related to a session;wherein the routing table is generated during transferring a sessionestablishment request of the session and records the address informationof at least one Authentication, Authorization and Accounting (AAA) proxyserver between the AAA client in the visited network of the terminal anda destination AAA server in a home network of the terminal, and transfera session request of the session carrying the routing table to a firstAAA proxy server of the visited network of the terminal according to theaddress information of the first AAA proxy server recorded in therouting table upon receiving the session request of the session sendingfrom the terminal; the first AAA proxy server, configured to receive thesession request of the session carrying the routing table, acquire aroute for sending the session request of the session, according to therouting table carried in the received session request; and transfer thesession request of the session carrying the routing table with a recordof the first AAA server deleted to an AAA proxy server of anintermediate network or the destination AAA server of the home networkof the terminal, according to the route for sending the session requestof the session; wherein: the AAA client of the visited network of theterminal and the first AAA proxy server are further configured totransfer each subsequent request of the session between the AAA clientand the destination AAA server through the first AAA proxy serveraccording to the routing table related to the session, so that allrequests of the session to be transferred via same AAA proxy servers.27. The system of claim 26, wherein the AAA client of the visitednetwork of the terminal is further configured to send a sessionestablishment request of the session to a first AAA proxy serverselected from the visited network of the terminal upon receiving thesession establishment request of the session from the terminal; thefirst AAA proxy server of the visited network of the terminal is furtherconfigured to write the address information of the first AAA proxyserver in the session establishment request of the session, and sendingthe session establishment request of the session to the destination AAAserver of the home network of the terminal; the destination AAA serverof the home network of the terminal is further configured to form therouting table related to the session, send the routing table related tothe session to the AAA client of the visited network of the terminal;and the AAA client of the visited network of the terminal is furtherconfigured to save the routing table related to the session.